Secure Authentication Of A Device Through Attestation By Another Device

ABSTRACT

Methods and systems for secure authentication of a first device through attestation by one or more other devices are described herein. A server may receive, from an untrusted client device, a request for access to one or more services associated with the server. The server may generate a challenge code. The server may send, to the untrusted client device, a request for attestation of the untrusted client device. The server may receive, from a trusted client device, an indication that the trusted client device attests to an identity of the untrusted client device. Based on the indication that the trusted client device attests to the identity of the untrusted client device, the server may grant, to the untrusted client device, access to the one or more services associated with the server.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No. 15/813,739, filed Nov. 15, 2017 and entitled “SECURE AUTHENTICATION OF A DEVICE THROUGH ATTESTATION BY ANOTHER DEVICE.” The prior application is herein incorporated by reference in its entirety for all purposes.

FIELD

Aspects described herein generally relate to computer networking and data security. More specifically, aspects described herein relate to secure authentication of a device through attestation by one or more other devices.

BACKGROUND

Two-factor authentication may be used to authenticate client devices. For example, one authentication factor may be a password, and a second authentication factor may be in the form of proof-of-possession (e.g., a security token) or biometrics (e.g., a fingerprint). Existing methods for this additional authentication factor may incur extra inefficiencies or costs, such as by requiring physical components (e.g., RSA tokens), or registration of sensitive personal information (e.g., fingerprints), and efforts of keeping that information current. What is needed is a system and method for performing secure authentication of, for example, untrusted devices without the extra inefficiencies or costs of conventional two-factor methods.

SUMMARY

The following presents a simplified summary of various aspects described herein. This summary is not an extensive overview, and is not intended to identify key or critical elements or to delineate the scope of the claims. The following summary merely presents some concepts in a simplified form as an introductory prelude to the more detailed description provided below.

A system, apparatus, or method described herein may comprise receiving, by a server device and from a client device, credentials for authenticating a user of the client device. The user of the client device may be authenticated based on the credentials. In response to authenticating the user, the server device may generate a challenge code. The server device may transmit, to the client device, a request for attestation of the client device, and the request for attestation may comprise the challenge code and an identifier for the server device. The server device may receive, from another client device, an indication that another client device attests to an identity of one or more of the client device or the user of the client device. Based on the indication that another client device attests to the identity of one or more of the client device or the user of the client device, the server device may transmit, to the client device, an indication that the client device has been granted access to one or more services associated with the server device.

In some aspects, the challenge code may comprise a one-time challenge code. Generating the challenge code may comprise generating the challenge code using a random number generator associated with the server device. Additionally or alternatively, the identifier for the server device may comprise a uniform resource identifier for the server device.

In some aspects, a method described herein may comprise determining one or more of a list of users or a group of users authorized for attestation of the client device. The server device may transmit, to the client device, data indicating the one or more of the list of users or the group of users authorized for attestation of the client device. In some aspects, receiving the indication that another client device attests to the identity of one or more of the client device or the user of the client device may be performed after an authentication of the another client device by a second server device.

In some aspects, the server device may receive, from another client device, the challenge code. Transmitting the indication that the client device has been granted access to one or more services may be based on a determination that the challenge code received from another client device corresponds to the challenge code generated by the server device. In some aspects, the server device may receive, from a third client device, an indication that the third client device attests to the identity of one or more of the client device or the user of the client device. Transmitting the indication that the client device has been granted access to one or more services may be based on the indication that the third client device attests to the identity of one or more of the client device or the user of the client device.

In some aspects, the server device may determine a level of access of the client device to a plurality of services associated with the server device based on a number of client devices attesting to the identity of one or more of the client device or the user of the client device. Additionally or alternatively, the server device may determine a level of access of the client device to the plurality of services associated with the server device based on a level of access of another client device to a plurality of services associated with the server device.

A system, apparatus, or method described herein may comprise transmitting, by a client device and to a server device, credentials for authenticating a user of the client device. The client device may receive, from the server device, a request for attestation of the client device, and the request for attestation may comprise a challenge code generated by the server device and an identifier for the server device. The method may comprise generating a code by encoding at least the challenge code, the identifier for the server device, and data identifying one or more of the client device or the user of the client device. The client device may display the code. The client device may receive, from the server device, an indication that the client device has been granted access to one or more services associated with the server device. The indication that the client device has been granted access may be based on an attestation of the client device by another client device.

In some aspects, the challenge code may comprise a one-time challenge code generated by a random number generator associated with the server device. Additionally or alternatively, the identifier for the server device may comprise a uniform resource identifier for the server device.

In some aspects, the client device may receive, from the server device, data indicating one or more of a list of users or a group of users for attestation of the client device. Displaying the code may comprise displaying, by the client device, the code and the one or more of the list of users or the group of users for attestation of the client device. In some aspects, the code may comprise a Quick Response (QR) code.

In some aspects, the indication that the client device has been granted access may be based on an attestation of the client device by a plurality of other client devices. The plurality of other client devices may comprise the another client device.

In some aspects, the client device may receive, from the server device, an indication of a number of attestations of the client device by other client devices. The client device may display the indication of the number of attestations of the client device by other client devices.

These and additional aspects will be appreciated with the benefit of the disclosures discussed in further detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of aspects described herein and the advantages thereof may be acquired by referring to the following description in consideration of the accompanying drawings, in which like reference numbers indicate like features, and wherein:

FIG. 1 depicts an illustrative computer system architecture that may be used in accordance with one or more illustrative aspects described herein.

FIG. 2 depicts an illustrative remote-access system architecture that may be used in accordance with one or more illustrative aspects described herein.

FIG. 3 depicts an illustrative virtualized (hypervisor) system architecture that may be used in accordance with one or more illustrative aspects described herein.

FIG. 4 depicts an illustrative cloud-based system architecture that may be used in accordance with one or more illustrative aspects described herein.

FIG. 5 depicts an illustrative enterprise mobility management system.

FIG. 6 depicts another illustrative enterprise mobility management system.

FIG. 7 depicts an illustrative system and method for secure authentication of a device through attestation by another device in accordance with one or more illustrative aspects described herein.

FIG. 8 depicts another illustrative system and method for secure authentication of a device through attestation by another device in accordance with one or more illustrative aspects described herein.

DETAILED DESCRIPTION

In the following description of the various embodiments, reference is made to the accompanying drawings identified above and which form a part hereof, and in which is shown by way of illustration various embodiments in which aspects described herein may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope described herein. Various aspects are capable of other embodiments and of being practiced or being carried out in various different ways.

It is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. Rather, the phrases and terms used herein are to be given their broadest interpretation and meaning. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. The use of the terms “mounted,” “connected,” “coupled,” “positioned,” “engaged” and similar terms, is meant to include both direct and indirect mounting, connecting, coupling, positioning and engaging.

Computing Architecture

Computer software, hardware, and networks may be utilized in a variety of different system environments, including standalone, networked, remote-access (also known as, remote desktop), virtualized, and/or cloud-based environments, among others. FIG. 1 illustrates one example of a system architecture and data processing device that may be used to implement one or more illustrative aspects described herein in a standalone and/or networked environment. Various network nodes 103, 105, 107, and 109 may be interconnected via a wide area network (WAN) 101, such as the Internet. Other networks may also or alternatively be used, including private intranets, corporate networks, LANs, metropolitan area networks (MAN) wireless networks, personal networks (PAN), and the like. Network 101 is for illustration purposes and may be replaced with fewer or additional computer networks. A local area network (LAN) may have one or more of any known LAN topology and may use one or more of a variety of different protocols, such as Ethernet. Devices 103, 105, 107, 109 and other devices (not shown) may be connected to one or more of the networks via twisted pair wires, coaxial cable, fiber optics, radio waves or other communication media.

The term “network” as used herein and depicted in the drawings refers not only to systems in which remote storage devices are coupled together via one or more communication paths, but also to stand-alone devices that may be coupled, from time to time, to such systems that have storage capability. Consequently, the term “network” includes not only a “physical network” but also a “content network,” which is comprised of the data—attributable to a single entity—which resides across all physical networks.

The components may include data server 103, web server 105, and client computers 107, 109. Data server 103 provides overall access, control and administration of databases and control software for performing one or more illustrative aspects describe herein. Data server 103 may be connected to web server 105 through which users interact with and obtain data as requested. Alternatively, data server 103 may act as a web server itself and be directly connected to the Internet. Data server 103 may be connected to web server 105 through the network 101 (e.g., the Internet), via direct or indirect connection, or via some other network. Users may interact with the data server 103 using remote computers 107, 109, e.g., using a web browser to connect to the data server 103 via one or more externally exposed web sites hosted by web server 105. Client computers 107, 109 may be used in concert with data server 103 to access data stored therein, or may be used for other purposes. For example, from client device 107 a user may access web server 105 using an Internet browser, as is known in the art, or by executing a software application that communicates with web server 105 and/or data server 103 over a computer network (such as the Internet).

Servers and applications may be combined on the same physical machines, and retain separate virtual or logical addresses, or may reside on separate physical machines. FIG. 1 illustrates just one example of a network architecture that may be used, and those of skill in the art will appreciate that the specific network architecture and data processing devices used may vary, and are secondary to the functionality that they provide, as further described herein. For example, services provided by web server 105 and data server 103 may be combined on a single server.

Each component 103, 105, 107, 109 may be any type of known computer, server, or data processing device. Data server 103, e.g., may include a processor 111 controlling overall operation of the data server 103. Data server 103 may further include random access memory (RAM) 113, read only memory (ROM) 115, network interface 117, input/output interfaces 119 (e.g., keyboard, mouse, display, printer, etc.), and memory 121. Input/output (I/O) 119 may include a variety of interface units and drives for reading, writing, displaying, and/or printing data or files. Memory 121 may further store operating system software 123 for controlling overall operation of the data processing device 103, control logic 125 for instructing data server 103 to perform aspects described herein, and other application software 127 providing secondary, support, and/or other functionality which may or might not be used in conjunction with aspects described herein. The control logic may also be referred to herein as the data server software 125. Functionality of the data server software may refer to operations or decisions made automatically based on rules coded into the control logic, made manually by a user providing input into the system, and/or a combination of automatic processing based on user input (e.g., queries, data updates, etc.).

Memory 121 may also store data used in performance of one or more aspects described herein, including a first database 129 and a second database 131. In some embodiments, the first database may include the second database (e.g., as a separate table, report, etc.). That is, the information can be stored in a single database, or separated into different logical, virtual, or physical databases, depending on system design. Devices 105, 107, 109 may have similar or different architecture as described with respect to device 103. Those of skill in the art will appreciate that the functionality of data processing device 103 (or device 105, 107, 109) as described herein may be spread across multiple data processing devices, for example, to distribute processing load across multiple computers, to segregate transactions based on geographic location, user access level, quality of service (QoS), etc.

One or more aspects may be embodied in computer-usable or readable data and/or computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices as described herein. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The modules may be written in a source code programming language that is subsequently compiled for execution, or may be written in a scripting language such as (but not limited to) HyperText Markup Language (HTML) or Extensible Markup Language (XML). The computer executable instructions may be stored on a computer readable medium such as a nonvolatile storage device. Any suitable computer readable storage media may be utilized, including hard disks, CD-ROMs, optical storage devices, magnetic storage devices, and/or any combination thereof. In addition, various transmission (non-storage) media representing data or events as described herein may be transferred between a source and a destination in the form of electromagnetic waves traveling through signal-conducting media such as metal wires, optical fibers, and/or wireless transmission media (e.g., air and/or space). Various aspects described herein may be embodied as a method, a data processing system, or a computer program product. Therefore, various functionalities may be embodied in whole or in part in software, firmware and/or hardware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA), and the like. Particular data structures may be used to more effectively implement one or more aspects described herein, and such data structures are contemplated within the scope of computer executable instructions and computer-usable data described herein.

With further reference to FIG. 2, one or more aspects described herein may be implemented in a remote-access environment. FIG. 2 depicts an example system architecture including a generic computing device 201 in an illustrative computing environment 200 that may be used according to one or more illustrative aspects described herein. Generic computing device 201 may be used as a server 206 a in a single-server or multi-server desktop virtualization system (e.g., a remote access or cloud system) configured to provide virtual machines for client access devices. The generic computing device 201 may have a processor 203 for controlling overall operation of the server and its associated components, including RAM 205, ROM 207, I/O module 209, and memory 215.

I/O module 209 may include a mouse, keypad, touch screen, scanner, optical reader, and/or stylus (or other input device(s)) through which a user of generic computing device 201 may provide input, and may also include one or more of a speaker for providing audio output and a video display device for providing textual, audiovisual, and/or graphical output. Software may be stored within memory 215 and/or other storage to provide instructions to processor 203 for configuring generic computing device 201 into a special purpose computing device in order to perform various functions as described herein. For example, memory 215 may store software used by the computing device 201, such as an operating system 217, application programs 219, and an associated database 221.

Computing device 201 may operate in a networked environment supporting connections to one or more remote computers, such as terminals 240 (also referred to as client devices). The terminals 240 may be personal computers, mobile devices, laptop computers, tablets, or servers that include many or all of the elements described above with respect to the generic computing device 103 or 201. The network connections depicted in FIG. 2 include a local area network (LAN) 225 and a wide area network (WAN) 229, but may also include other networks. When used in a LAN networking environment, computing device 201 may be connected to the LAN 225 through a network interface or adapter 223. When used in a WAN networking environment, computing device 201 may include a modem 227 or other wide area network interface for establishing communications over the WAN 229, such as computer network 230 (e.g., the Internet). It will be appreciated that the network connections shown are illustrative and other means of establishing a communications link between the computers may be used. Computing device 201 and/or terminals 240 may also be mobile terminals (e.g., mobile phones, smartphones, personal digital assistants (PDAs), notebooks, etc.) including various other components, such as a battery, speaker, and antennas (not shown).

Aspects described herein may also be operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of other computing systems, environments, and/or configurations that may be suitable for use with aspects described herein include, but are not limited to, personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network personal computers (PCs), minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.

As shown in FIG. 2, one or more client devices 240 may be in communication with one or more servers 206 a-206 n (generally referred to herein as “server(s) 206”). In one embodiment, the computing environment 200 may include a network appliance installed between the server(s) 206 and client machine(s) 240. The network appliance may manage client/server connections, and in some cases can load balance client connections amongst a plurality of backend servers 206.

The client machine(s) 240 may in some embodiments be referred to as a single client machine 240 or a single group of client machines 240, while server(s) 206 may be referred to as a single server 206 or a single group of servers 206. In one embodiment a single client machine 240 communicates with more than one server 206, while in another embodiment a single server 206 communicates with more than one client machine 240. In yet another embodiment, a single client machine 240 communicates with a single server 206.

A client machine 240 can, in some embodiments, be referenced by any one of the following non-exhaustive terms: client machine(s); client(s); client computer(s); client device(s); client computing device(s); local machine; remote machine; client node(s); endpoint(s); or endpoint node(s). The server 206, in some embodiments, may be referenced by any one of the following non-exhaustive terms: server(s), local machine; remote machine; server farm(s), or host computing device(s).

In one embodiment, the client machine 240 may be a virtual machine. The virtual machine may be any virtual machine, while in some embodiments the virtual machine may be any virtual machine managed by a Type 1 or Type 2 hypervisor, for example, a hypervisor developed by Citrix Systems, IBM, VMware, or any other hypervisor. In some aspects, the virtual machine may be managed by a hypervisor, while in aspects the virtual machine may be managed by a hypervisor executing on a server 206 or a hypervisor executing on a client 240.

Some embodiments include a client device 240 that displays application output generated by an application remotely executing on a server 206 or other remotely located machine. In these embodiments, the client device 240 may execute a virtual machine receiver program or application to display the output in an application window, a browser, or other output window. In one example, the application is a desktop, while in other examples the application is an application that generates or presents a desktop. A desktop may include a graphical shell providing a user interface for an instance of an operating system in which local and/or remote applications can be integrated. Applications, as used herein, are programs that execute after an instance of an operating system (and, optionally, also the desktop) has been loaded.

The server 206, in some embodiments, uses a remote presentation protocol or other program to send data to a thin-client or remote-display application executing on the client to present display output generated by an application executing on the server 206. The thin-client or remote-display protocol can be any one of the following non-exhaustive list of protocols: the Independent Computing Architecture (ICA) protocol developed by Citrix Systems, Inc. of Ft. Lauderdale, Fla.; or the Remote Desktop Protocol (RDP) manufactured by the Microsoft Corporation of Redmond, Wash.

A remote computing environment may include more than one server 206 a-206 n such that the servers 206 a-206 n are logically grouped together into a server farm 206, for example, in a cloud computing environment. The server farm 206 may include servers 206 that are geographically dispersed while and logically grouped together, or servers 206 that are located proximate to each other while logically grouped together. Geographically dispersed servers 206 a-206 n within a server farm 206 can, in some embodiments, communicate using a WAN (wide), MAN (metropolitan), or LAN (local), where different geographic regions can be characterized as: different continents; different regions of a continent; different countries; different states; different cities; different campuses; different rooms; or any combination of the preceding geographical locations. In some embodiments the server farm 206 may be administered as a single entity, while in other embodiments the server farm 206 can include multiple server farms.

In some embodiments, a server farm may include servers 206 that execute a substantially similar type of operating system platform (e.g., WINDOWS, UNIX, LINUX, iOS, ANDROID, SYMBIAN, etc.) In other embodiments, server farm 206 may include a first group of one or more servers that execute a first type of operating system platform, and a second group of one or more servers that execute a second type of operating system platform.

Server 206 may be configured as any type of server, as needed, e.g., a file server, an application server, a web server, a proxy server, an appliance, a network appliance, a gateway, an application gateway, a gateway server, a virtualization server, a deployment server, a Secure Sockets Layer (SSL) VPN server, a firewall, a web server, an application server or as a master application server, a server executing an active directory, or a server executing an application acceleration program that provides firewall functionality, application functionality, or load balancing functionality. Other server types may also be used.

Some embodiments include a first server 206 a that receives requests from a client machine 240, forwards the request to a second server 206 b, and responds to the request generated by the client machine 240 with a response from the second server 206 b. First server 206 a may acquire an enumeration of applications available to the client machine 240 and well as address information associated with an application server 206 hosting an application identified within the enumeration of applications. First server 206 a can then present a response to the client's request using a web interface, and communicate directly with the client 240 to provide the client 240 with access to an identified application. One or more clients 240 and/or one or more servers 206 may transmit data over network 230, e.g., network 101.

FIG. 2 shows a high-level architecture of an illustrative desktop virtualization system. As shown, the desktop virtualization system may be single-server or multi-server system, or cloud system, including at least one virtualization server 206 configured to provide virtual desktops and/or virtual applications to one or more client access devices 240. As used herein, a desktop refers to a graphical environment or space in which one or more applications may be hosted and/or executed. A desktop may include a graphical shell providing a user interface for an instance of an operating system in which local and/or remote applications can be integrated. Applications may include programs that execute after an instance of an operating system (and, optionally, also the desktop) has been loaded. Each instance of the operating system may be physical (e.g., one operating system per device) or virtual (e.g., many instances of an OS running on a single device). Each application may be executed on a local device, or executed on a remotely located device (e.g., remoted).

With further reference to FIG. 3, a computer device 301 may be configured as a virtualization server in a virtualization environment, for example, a single-server, multi-server, or cloud-computing environment. Virtualization server 301 illustrated in FIG. 3 can be deployed as and/or implemented by one or more embodiments of the server 206 illustrated in FIG. 2 or by other known computing devices. Included in virtualization server 301 is a hardware layer that can include one or more physical disks 304, one or more physical devices 306, one or more physical processors 308 and one or more physical memories 316. In some embodiments, firmware 312 can be stored within a memory element in the physical memory 316 and can be executed by one or more of the physical processors 308. Virtualization server 301 may further include an operating system 314 that may be stored in a memory element in the physical memory 316 and executed by one or more of the physical processors 308. Still further, a hypervisor 302 may be stored in a memory element in the physical memory 316 and can be executed by one or more of the physical processors 308.

Executing on one or more of the physical processors 308 may be one or more virtual machines 332A-C (generally 332). Each virtual machine 332 may have a virtual disk 326A-C and a virtual processor 328A-C. In some embodiments, a first virtual machine 332A may execute, using a virtual processor 328A, a control program 320 that includes a tools stack 324. Control program 320 may be referred to as a control virtual machine, Dom0, Domain 0, or other virtual machine used for system administration and/or control. In some embodiments, one or more virtual machines 332B-C can execute, using a virtual processor 328B-C, a guest operating system 330A-B.

Virtualization server 301 may include a hardware layer 310 with one or more pieces of hardware that communicate with the virtualization server 301. In some embodiments, the hardware layer 310 can include one or more physical disks 304, one or more physical devices 306, one or more physical processors 308, and one or more memory 316. Physical components 304, 306, 308, and 316 may include, for example, any of the components described above. Physical devices 306 may include, for example, a network interface card, a video card, a keyboard, a mouse, an input device, a monitor, a display device, speakers, an optical drive, a storage device, a universal serial bus connection, a printer, a scanner, a network element (e.g., router, firewall, network address translator, load balancer, virtual private network (VPN) gateway, Dynamic Host Configuration Protocol (DHCP) router, etc.), or any device connected to or communicating with virtualization server 301. Physical memory 316 in the hardware layer 310 may include any type of memory. Physical memory 316 may store data, and in some embodiments may store one or more programs, or set of executable instructions. FIG. 3 illustrates an embodiment where firmware 312 is stored within the physical memory 316 of virtualization server 301. Programs or executable instructions stored in the physical memory 316 can be executed by the one or more processors 308 of virtualization server 301.

Virtualization server 301 may also include a hypervisor 302. In some embodiments, hypervisor 302 may be a program executed by processors 308 on virtualization server 301 to create and manage any number of virtual machines 332. Hypervisor 302 may be referred to as a virtual machine monitor, or platform virtualization software. In some embodiments, hypervisor 302 can be any combination of executable instructions and hardware that monitors virtual machines executing on a computing machine. Hypervisor 302 may be Type 2 hypervisor, where the hypervisor that executes within an operating system 314 executing on the virtualization server 301. Virtual machines then execute at a level above the hypervisor. In some embodiments, the Type 2 hypervisor executes within the context of a user's operating system such that the Type 2 hypervisor interacts with the user's operating system. In other embodiments, one or more virtualization servers 301 in a virtualization environment may instead include a Type 1 hypervisor (not shown). A Type 1 hypervisor may execute on the virtualization server 301 by directly accessing the hardware and resources within the hardware layer 310. That is, while a Type 2 hypervisor 302 accesses system resources through a host operating system 314, as shown, a Type 1 hypervisor may directly access all system resources without the host operating system 314. A Type 1 hypervisor may execute directly on one or more physical processors 308 of virtualization server 301, and may include program data stored in the physical memory 316.

Hypervisor 302, in some embodiments, can provide virtual resources to operating systems 330 or control programs 320 executing on virtual machines 332 in any manner that simulates the operating systems 330 or control programs 320 having direct access to system resources. System resources can include, but are not limited to, physical devices 306, physical disks 304, physical processors 308, physical memory 316 and any other component included in virtualization server 301 hardware layer 310. Hypervisor 302 may be used to emulate virtual hardware, partition physical hardware, virtualize physical hardware, and/or execute virtual machines that provide access to computing environments. In still other embodiments, hypervisor 302 controls processor scheduling and memory partitioning for a virtual machine 332 executing on virtualization server 301. Hypervisor 302 may include those manufactured by VMWare, Inc., of Palo Alto, Calif.; the XEN hypervisor, an open source product whose development is overseen by the open source Xen.org community; HyperV, VirtualServer or virtual PC hypervisors provided by Microsoft, or others. In some embodiments, virtualization server 301 executes a hypervisor 302 that creates a virtual machine platform on which guest operating systems may execute. In these embodiments, the virtualization server 301 may be referred to as a host server. An example of such a virtualization server is the XEN SERVER provided by Citrix Systems, Inc., of Fort Lauderdale, Fla.

Hypervisor 302 may create one or more virtual machines 332B-C (generally 332) in which guest operating systems 330 execute. In some embodiments, hypervisor 302 may load a virtual machine image to create a virtual machine 332. In other embodiments, the hypervisor 302 may executes a guest operating system 330 within virtual machine 332. In still other embodiments, virtual machine 332 may execute guest operating system 330.

In addition to creating virtual machines 332, hypervisor 302 may control the execution of at least one virtual machine 332. In other embodiments, hypervisor 302 may presents at least one virtual machine 332 with an abstraction of at least one hardware resource provided by the virtualization server 301 (e.g., any hardware resource available within the hardware layer 310). In other embodiments, hypervisor 302 may control the manner in which virtual machines 332 access physical processors 308 available in virtualization server 301. Controlling access to physical processors 308 may include determining whether a virtual machine 332 should have access to a processor 308, and how physical processor capabilities are presented to the virtual machine 332.

As shown in FIG. 3, virtualization server 301 may host or execute one or more virtual machines 332. A virtual machine 332 is a set of executable instructions that, when executed by a processor 308, imitate the operation of a physical computer such that the virtual machine 332 can execute programs and processes much like a physical computing device. While FIG. 3 illustrates an embodiment where a virtualization server 301 hosts three virtual machines 332, in other embodiments virtualization server 301 can host any number of virtual machines 332. Hypervisor 302, in some embodiments, provides each virtual machine 332 with a unique virtual view of the physical hardware, memory, processor and other system resources available to that virtual machine 332. In some embodiments, the unique virtual view can be based on one or more of virtual machine permissions, application of a policy engine to one or more virtual machine identifiers, a user accessing a virtual machine, the applications executing on a virtual machine, networks accessed by a virtual machine, or any other desired criteria. For instance, hypervisor 302 may create one or more unsecure virtual machines 332 and one or more secure virtual machines 332. Unsecure virtual machines 332 may be prevented from accessing resources, hardware, memory locations, and programs that secure virtual machines 332 may be permitted to access. In other embodiments, hypervisor 302 may provide each virtual machine 332 with a substantially similar virtual view of the physical hardware, memory, processor and other system resources available to the virtual machines 332.

Each virtual machine 332 may include a virtual disk 326A-C (generally 326) and a virtual processor 328A-C (generally 328.) The virtual disk 326, in some embodiments, is a virtualized view of one or more physical disks 304 of the virtualization server 301, or a portion of one or more physical disks 304 of the virtualization server 301. The virtualized view of the physical disks 304 can be generated, provided and managed by the hypervisor 302. In some embodiments, hypervisor 302 provides each virtual machine 332 with a unique view of the physical disks 304. Thus, in these embodiments, the particular virtual disk 326 included in each virtual machine 332 can be unique when compared with the other virtual disks 326.

A virtual processor 328 can be a virtualized view of one or more physical processors 308 of the virtualization server 301. In some embodiments, the virtualized view of the physical processors 308 can be generated, provided and managed by hypervisor 302. In some embodiments, virtual processor 328 has substantially all of the same characteristics of at least one physical processor 308. In other embodiments, virtual processor 308 provides a modified view of physical processors 308 such that at least some of the characteristics of the virtual processor 328 are different than the characteristics of the corresponding physical processor 308.

With further reference to FIG. 4, some aspects described herein may be implemented in a cloud-based environment. FIG. 4 illustrates an example of a cloud computing environment (or cloud system) 400. As seen in FIG. 4, client computers 411-414 may communicate with a cloud management server 410 to access the computing resources (e.g., host servers 403, storage resources 404, and network resources 405) of the cloud system.

Management server 410 may be implemented on one or more physical servers. The management server 410 may run, for example, CLOUDSTACK, or OPENSTACK, among others. Management server 410 may manage various computing resources, including cloud hardware and software resources, for example, host computers 403, data storage devices 404, and networking devices 405. The cloud hardware and software resources may include private and/or public components. For example, a cloud may be configured as a private cloud to be used by one or more particular customers or client computers 411-414 and/or over a private network. In other embodiments, public clouds or hybrid public-private clouds may be used by other customers over an open or hybrid networks.

Management server 410 may be configured to provide user interfaces through which cloud operators and cloud customers may interact with the cloud system. For example, the management server 410 may provide a set of application programming interfaces (APIs) and/or one or more cloud operator console applications (e.g., web-based on standalone applications) with user interfaces to allow cloud operators to manage the cloud resources, configure the virtualization layer, manage customer accounts, and perform other cloud administration tasks. The management server 410 also may include a set of APIs and/or one or more customer console applications with user interfaces configured to receive cloud computing requests from end users via client computers 411-414, for example, requests to create, modify, or destroy virtual machines within the cloud. Client computers 411-414 may connect to management server 410 via the Internet or other communication network, and may request access to one or more of the computing resources managed by management server 410. In response to client requests, the management server 410 may include a resource manager configured to select and provision physical resources in the hardware layer of the cloud system based on the client requests. For example, the management server 410 and additional components of the cloud system may be configured to provision, create, and manage virtual machines and their operating environments (e.g., hypervisors, storage resources, services offered by the network elements, etc.) for customers at client computers 411-414, over a network (e.g., the Internet), providing customers with computational resources, data storage services, networking capabilities, and computer platform and application support. Cloud systems also may be configured to provide various specific services, including security systems, development environments, user interfaces, and the like.

Certain clients 411-414 may be related, for example, different client computers creating virtual machines on behalf of the same end user, or different users affiliated with the same company or organization. In other examples, certain clients 411-414 may be unrelated, such as users affiliated with different companies or organizations. For unrelated clients, information on the virtual machines or storage of any one user may be hidden from other users.

Referring now to the physical hardware layer of a cloud computing environment, availability zones 401-402 (or zones) may refer to a collocated set of physical computing resources. Zones may be geographically separated from other zones in the overall cloud of computing resources. For example, zone 401 may be a first cloud datacenter located in California, and zone 402 may be a second cloud datacenter located in Florida. Management sever 410 may be located at one of the availability zones, or at a separate location. Each zone may include an internal network that interfaces with devices that are outside of the zone, such as the management server 410, through a gateway. End users of the cloud (e.g., clients 411-414) might or might not be aware of the distinctions between zones. For example, an end user may request the creation of a virtual machine having a specified amount of memory, processing power, and network capabilities. The management server 410 may respond to the user's request and may allocate the resources to create the virtual machine without the user knowing whether the virtual machine was created using resources from zone 401 or zone 402. In other examples, the cloud system may allow end users to request that virtual machines (or other cloud resources) are allocated in a specific zone or on specific resources 403-405 within a zone.

In this example, each zone 401-402 may include an arrangement of various physical hardware components (or computing resources) 403-405, for example, physical hosting resources (or processing resources), physical network resources, physical storage resources, switches, and additional hardware resources that may be used to provide cloud computing services to customers. The physical hosting resources in a cloud zone 401-402 may include one or more computer servers 403, such as the virtualization servers 301 described above, which may be configured to create and host virtual machine instances. The physical network resources in a cloud zone 401 or 402 may include one or more network elements 405 (e.g., network service providers) comprising hardware and/or software configured to provide a network service to cloud customers, such as firewalls, network address translators, load balancers, virtual private network (VPN) gateways, Dynamic Host Configuration Protocol (DHCP) routers, and the like. The storage resources in the cloud zone 401-402 may include storage disks (e.g., solid state drives (SSDs), magnetic hard disks, etc.) and other storage devices.

The example cloud computing environment shown in FIG. 4 also may include a virtualization layer (e.g., as shown in FIGS. 1-3) with additional hardware and/or software resources configured to create and manage virtual machines and provide other services to customers using the physical resources in the cloud. The virtualization layer may include hypervisors, as described above in FIG. 3, along with other components to provide network virtualizations, storage virtualizations, etc. The virtualization layer may be as a separate layer from the physical resource layer, or may share some or all of the same hardware and/or software resources with the physical resource layer. For example, the virtualization layer may include a hypervisor installed in each of the virtualization servers 403 with the physical computing resources. Known cloud systems may alternatively be used, e.g., WINDOWS AZURE (Microsoft Corporation of Redmond Wash.), AMAZON EC2 (Amazon.com Inc. of Seattle, Wash.), IBM BLUE CLOUD (IBM Corporation of Armonk, N.Y.), or others.

Enterprise Mobility Management Architecture

FIG. 5 represents an enterprise mobility technical architecture 500 for use in a BYOD environment. The architecture enables a user of a mobile device 502 to both access enterprise or personal resources from a mobile device 502 and use the mobile device 502 for personal use. The user may access such enterprise resources 504 or enterprise services 508 using a mobile device 502 that is purchased by the user or a mobile device 502 that is provided by the enterprise to user. The user may utilize the mobile device 502 for business use only or for business and personal use. The mobile device may run an iOS operating system, and Android operating system, or the like. The enterprise may choose to implement policies to manage the mobile device 504. The policies may be implanted through a firewall or gateway in such a way that the mobile device may be identified, secured or security verified, and provided selective or full access to the enterprise resources. The policies may be mobile device management policies, mobile application management policies, mobile data management policies, or some combination of mobile device, application, and data management policies. A mobile device 504 that is managed through the application of mobile device management policies may be referred to as an enrolled device.

In some embodiments, the operating system of the mobile device may be separated into a managed partition 510 and an unmanaged partition 512. The managed partition 510 may have policies applied to it to secure the applications running on and data stored in the managed partition. The applications running on the managed partition may be secure applications. In other embodiments, all applications may execute in accordance with a set of one or more policy files received separate from the application, and which define one or more security parameters, features, resource restrictions, and/or other access controls that are enforced by the mobile device management system when that application is executing on the device. By operating in accordance with their respective policy file(s), each application may be allowed or restricted from communications with one or more other applications and/or resources, thereby creating a virtual partition. Thus, as used herein, a partition may refer to a physically partitioned portion of memory (physical partition), a logically partitioned portion of memory (logical partition), and/or a virtual partition created as a result of enforcement of one or more policies and/or policy files across multiple apps as described herein (virtual partition). Stated differently, by enforcing policies on managed apps, those apps may be restricted to only be able to communicate with other managed apps and trusted enterprise resources, thereby creating a virtual partition that is not accessible by unmanaged apps and devices.

The secure applications may be email applications, web browsing applications, software-as-a-service (SaaS) access applications, Windows Application access applications, and the like. The secure applications may be secure native applications 514, secure remote applications 522 executed by a secure application launcher 518, virtualization applications 526 executed by a secure application launcher 518, and the like. The secure native applications 514 may be wrapped by a secure application wrapper 520. The secure application wrapper 520 may include integrated policies that are executed on the mobile device 502 when the secure native application is executed on the device. The secure application wrapper 520 may include meta-data that points the secure native application 514 running on the mobile device 502 to the resources hosted at the enterprise that the secure native application 514 may require to complete the task requested upon execution of the secure native application 514. The secure remote applications 522 executed by a secure application launcher 518 may be executed within the secure application launcher application 518. The virtualization applications 526 executed by a secure application launcher 518 may utilize resources on the mobile device 502, at the enterprise resources 504, and the like. The resources used on the mobile device 502 by the virtualization applications 526 executed by a secure application launcher 518 may include user interaction resources, processing resources, and the like. The user interaction resources may be used to collect and transmit keyboard input, mouse input, camera input, tactile input, audio input, visual input, gesture input, and the like. The processing resources may be used to present a user interface, process data received from the enterprise resources 504, and the like. The resources used at the enterprise resources 504 by the virtualization applications 526 executed by a secure application launcher 518 may include user interface generation resources, processing resources, and the like. The user interface generation resources may be used to assemble a user interface, modify a user interface, refresh a user interface, and the like. The processing resources may be used to create information, read information, update information, delete information, and the like. For example, the virtualization application may record user interactions associated with a graphical user interface (GUI) and communicate them to a server application where the server application may use the user interaction data as an input to the application operating on the server. In this arrangement, an enterprise may elect to maintain the application on the server side as well as data, files, etc. associated with the application. While an enterprise may elect to “mobilize” some applications in accordance with the principles herein by securing them for deployment on the mobile device, this arrangement may also be elected for certain applications. For example, while some applications may be secured for use on the mobile device, others might not be prepared or appropriate for deployment on the mobile device so the enterprise may elect to provide the mobile user access to the unprepared applications through virtualization techniques. As another example, the enterprise may have large complex applications with large and complex data sets (e.g., material resource planning applications) where it would be very difficult, or otherwise undesirable, to customize the application for the mobile device so the enterprise may elect to provide access to the application through virtualization techniques. As yet another example, the enterprise may have an application that maintains highly secured data (e.g., human resources data, customer data, engineering data) that may be deemed by the enterprise as too sensitive for even the secured mobile environment so the enterprise may elect to use virtualization techniques to permit mobile access to such applications and data. An enterprise may elect to provide both fully secured and fully functional applications on the mobile device as well as a virtualization application to allow access to applications that are deemed more properly operated on the server side. In an embodiment, the virtualization application may store some data, files, etc. on the mobile phone in one of the secure storage locations. An enterprise, for example, may elect to allow certain information to be stored on the phone while not permitting other information.

In connection with the virtualization application, as described herein, the mobile device may have a virtualization application that is designed to present GUIs and then record user interactions with the GUI. The application may communicate the user interactions to the server side to be used by the server side application as user interactions with the application. In response, the application on the server side may transmit back to the mobile device a new GUI. For example, the new GUI may be a static page, a dynamic page, an animation, or the like, thereby providing access to remotely located resources.

The secure applications may access data stored in a secure data container 528 in the managed partition 510 of the mobile device. The data secured in the secure data container may be accessed by the secure wrapped applications 514, applications executed by a secure application launcher 522, virtualization applications 526 executed by a secure application launcher 522, and the like. The data stored in the secure data container 528 may include files, databases, and the like. The data stored in the secure data container 528 may include data restricted to a specific secure application 530, shared among secure applications 532, and the like. Data restricted to a secure application may include secure general data 534 and highly secure data 538. Secure general data may use a strong form of encryption such as Advanced Encryption Standard (AES) 128-bit encryption or the like, while highly secure data 538 may use a very strong form of encryption such as AES 256-bit encryption. Data stored in the secure data container 528 may be deleted from the device upon receipt of a command from the device manager 524. The secure applications may have a dual-mode option 540. The dual mode option 540 may present the user with an option to operate the secured application in an unsecured or unmanaged mode. In an unsecured or unmanaged mode, the secure applications may access data stored in an unsecured data container 542 on the unmanaged partition 512 of the mobile device 502. The data stored in an unsecured data container may be personal data 544. The data stored in an unsecured data container 542 may also be accessed by unsecured applications 548 that are running on the unmanaged partition 512 of the mobile device 502. The data stored in an unsecured data container 542 may remain on the mobile device 502 when the data stored in the secure data container 528 is deleted from the mobile device 502. An enterprise may want to delete from the mobile device selected or all data, files, and/or applications owned, licensed or controlled by the enterprise (enterprise data) while leaving or otherwise preserving personal data, files, and/or applications owned, licensed or controlled by the user (personal data). This operation may be referred to as a selective wipe. With the enterprise and personal data arranged in accordance to the aspects described herein, an enterprise may perform a selective wipe.

The mobile device 502 may connect to enterprise resources 504 and enterprise services 508 at an enterprise, to the public Internet 548, and the like. The mobile device may connect to enterprise resources 504 and enterprise services 508 through virtual private network connections. The virtual private network connections, also referred to as microVPN or application-specific VPN, may be specific to particular applications (e.g., as illustrated by microVPNs 550), particular devices, particular secured areas on the mobile device (e.g., as illustrated by O/S VPN 552), and the like. For example, each of the wrapped applications in the secured area of the phone may access enterprise resources through an application specific VPN such that access to the VPN would be granted based on attributes associated with the application, possibly in conjunction with user or device attribute information. The virtual private network connections may carry Microsoft Exchange traffic, Microsoft Active Directory traffic, HyperText Transfer Protocol (HTTP) traffic, HyperText Transfer Protocol Secure (HTTPS) traffic, application management traffic, and the like. The virtual private network connections may support and enable single-sign-on authentication processes 554. The single-sign-on processes may allow a user to provide a single set of authentication credentials, which are then verified by an authentication service 558. The authentication service 558 may then grant to the user access to multiple enterprise resources 504, without requiring the user to provide authentication credentials to each individual enterprise resource 504.

The virtual private network connections may be established and managed by an access gateway 560. The access gateway 560 may include performance enhancement features that manage, accelerate, and improve the delivery of enterprise resources 504 to the mobile device 502. The access gateway may also re-route traffic from the mobile device 502 to the public Internet 548, enabling the mobile device 502 to access publicly available and unsecured applications that run on the public Internet 548. The mobile device may connect to the access gateway via a transport network 562. The transport network 562 may use one or more transport protocols and may be a wired network, wireless network, cloud network, local area network, metropolitan area network, wide area network, public network, private network, and the like.

The enterprise resources 504 may include email servers, file sharing servers, SaaS applications, Web application servers, Windows application servers, and the like. Email servers may include Exchange servers, Lotus Notes servers, and the like. File sharing servers may include ShareFile servers, and the like. SaaS applications may include Salesforce, and the like. Windows application servers may include any application server that is built to provide applications that are intended to run on a local Windows operating system, and the like. The enterprise resources 504 may be premise-based resources, cloud based resources, and the like. The enterprise resources 504 may be accessed by the mobile device 502 directly or through the access gateway 560. The enterprise resources 504 may be accessed by the mobile device 502 via a transport network 562. The transport network 562 may be a wired network, wireless network, cloud network, local area network, metropolitan area network, wide area network, public network, private network, and the like.

The enterprise services 508 may include authentication services 558, threat detection services 564, device manager services 524, file sharing services 568, policy manager services 570, social integration services 572, application controller services 574, and the like. Authentication services 558 may include user authentication services, device authentication services, application authentication services, data authentication services and the like. Authentication services 558 may use certificates. The certificates may be stored on the mobile device 502, by the enterprise resources 504, and the like. The certificates stored on the mobile device 502 may be stored in an encrypted location on the mobile device, the certificate may be temporarily stored on the mobile device 502 for use at the time of authentication, and the like. Threat detection services 564 may include intrusion detection services, unauthorized access attempt detection services, and the like. Unauthorized access attempt detection services may include unauthorized attempts to access devices, applications, data, and the like. Device management services 524 may include configuration, provisioning, security, support, monitoring, reporting, and decommissioning services. File sharing services 568 may include file management services, file storage services, file collaboration services, and the like. Policy manager services 570 may include device policy manager services, application policy manager services, data policy manager services, and the like. Social integration services 572 may include contact integration services, collaboration services, integration with social networks such as Facebook, Twitter, and LinkedIn, and the like. Application controller services 574 may include management services, provisioning services, deployment services, assignment services, revocation services, wrapping services, and the like.

The enterprise mobility technical architecture 500 may include an application store 578. The application store 578 may include unwrapped applications 580, pre-wrapped applications 582, and the like. Applications may be populated in the application store 578 from the application controller 574. The application store 578 may be accessed by the mobile device 502 through the access gateway 560, through the public Internet 548, or the like. The application store may be provided with an intuitive and easy to use User Interface.

A software development kit 584 may provide a user the capability to secure applications selected by the user by wrapping the application as described previously in this description. An application that has been wrapped using the software development kit 584 may then be made available to the mobile device 502 by populating it in the application store 578 using the application controller 574.

The enterprise mobility technical architecture 500 may include a management and analytics capability. The management and analytics capability may provide information related to how resources are used, how often resources are used, and the like. Resources may include devices, applications, data, and the like. How resources are used may include which devices download which applications, which applications access which data, and the like. How often resources are used may include how often an application has been downloaded, how many times a specific set of data has been accessed by an application, and the like.

FIG. 6 is another illustrative enterprise mobility management system 600. Some of the components of the mobility management system 500 described above with reference to FIG. 5 have been omitted for the sake of simplicity. The architecture of the system 600 depicted in FIG. 6 is similar in many respects to the architecture of the system 500 described above with reference to FIG. 5 and may include additional features not mentioned above.

In this case, the left hand side represents an enrolled mobile device 602 with a client agent 604, which interacts with gateway server 606 (which includes Access Gateway and application controller functionality) to access various enterprise resources 608 and services 609 such as Exchange, Sharepoint, public-key infrastructure (PKI) Resources, Kerberos Resources, Certificate Issuance service, as shown on the right hand side above. Although not specifically shown, the mobile device 602 may also interact with an enterprise application store (StoreFront) for the selection and downloading of applications.

The client agent 604 acts as the UI (user interface) intermediary for Windows apps/desktops hosted in an Enterprise data center, which are accessed using the High-Definition User Experience (HDX)/ICA display remoting protocol. The client agent 604 also supports the installation and management of native applications on the mobile device 602, such as native iOS or Android applications. For example, the managed applications 610 (mail, browser, wrapped application) shown in the figure above are all native applications that execute locally on the device. Client agent 604 and application management framework of this architecture act to provide policy driven management capabilities and features such as connectivity and SSO (single sign on) to enterprise resources/services 608. The client agent 604 handles primary user authentication to the enterprise, normally to Access Gateway (AG) with SSO to other gateway server components. The client agent 604 obtains policies from gateway server 606 to control the behavior of the managed applications 610 on the mobile device 602.

The Secure interprocess communication (IPC) links 612 between the native applications 610 and client agent 604 represent a management channel, which allows client agent to supply policies to be enforced by the application management framework 614 “wrapping” each application. The IPC channel 612 also allows client agent 604 to supply credential and authentication information that enables connectivity and SSO to enterprise resources 608. Finally, the IPC channel 612 allows the application management framework 614 to invoke user interface functions implemented by client agent 604, such as online and offline authentication.

Communications between the client agent 604 and gateway server 606 are essentially an extension of the management channel from the application management framework 614 wrapping each native managed application 610. The application management framework 614 requests policy information from client agent 604, which in turn requests it from gateway server 606. The application management framework 614 requests authentication, and client agent 604 logs into the gateway services part of gateway server 606 (also known as NetScaler Access Gateway). Client agent 604 may also call supporting services on gateway server 606, which may produce input material to derive encryption keys for the local data vaults 616, or provide client certificates which may enable direct authentication to PKI protected resources, as more fully explained below.

In more detail, the application management framework 614 “wraps” each managed application 610. This may be incorporated via an explicit build step, or via a post-build processing step. The application management framework 614 may “pair” with client agent 604 on first launch of an application 610 to initialize the Secure IPC channel and obtain the policy for that application. The application management framework 614 may enforce relevant portions of the policy that apply locally, such as the client agent login dependencies and some of the containment policies that restrict how local OS services may be used, or how they may interact with the application 610.

The application management framework 614 may use services provided by client agent 604 over the Secure IPC channel 612 to facilitate authentication and internal network access. Key management for the private and shared data vaults 616 (containers) may be also managed by appropriate interactions between the managed applications 610 and client agent 604. Vaults 616 may be available only after online authentication, or may be made available after offline authentication if allowed by policy. First use of vaults 616 may require online authentication, and offline access may be limited to at most the policy refresh period before online authentication is again required.

Network access to internal resources may occur directly from individual managed applications 610 through Access Gateway 606. The application management framework 614 is responsible for orchestrating the network access on behalf of each application 610. Client agent 604 may facilitate these network connections by providing suitable time limited secondary credentials obtained following online authentication. Multiple modes of network connection may be used, such as reverse web proxy connections and end-to-end VPN-style tunnels 618.

The Mail and Browser managed applications 610 have special status and may make use of facilities that might not be generally available to arbitrary wrapped applications. For example, the Mail application may use a special background network access mechanism that allows it to access Exchange over an extended period of time without requiring a full AG logon. The Browser application may use multiple private data vaults to segregate different kinds of data.

This architecture supports the incorporation of various other security features. For example, gateway server 606 (including its gateway services) in some cases might not need to validate active directory (AD) passwords. It can be left to the discretion of an enterprise whether an AD password is used as an authentication factor for some users in some situations. Different authentication methods may be used if a user is online or offline (i.e., connected or not connected to a network).

Step up authentication is a feature wherein gateway server 606 may identify managed native applications 610 that are allowed to have access to more sensitive data using strong authentication, and ensure that access to these applications is only permitted after performing appropriate authentication, even if this means a re-authentication is requested from the user after a prior weaker level of login.

Another security feature of this solution is the encryption of the data vaults 616 (containers) on the mobile device 602. The vaults 616 may be encrypted so that all on-device data including files, databases, and configurations are protected. For on-line vaults, the keys may be stored on the server (gateway server 606), and for off-line vaults, a local copy of the keys may be protected by a user password or biometric validation. When data is stored locally on the device 602 in the secure container 616, it is preferred that a minimum of AES 256 encryption algorithm be utilized.

Other secure container features may also be implemented. For example, a logging feature may be included, wherein all security events happening inside an application 610 are logged and reported to the backend. Data wiping may be supported, such as if the application 610 detects tampering, associated encryption keys may be written over with random data, leaving no hint on the file system that user data was destroyed. Screenshot protection is another feature, where an application may prevent any data from being stored in screenshots. For example, the key window's hidden property may be set to YES. This may cause whatever content is currently displayed on the screen to be hidden, resulting in a blank screenshot where any content would normally reside.

Local data transfer may be prevented, such as by preventing any data from being locally transferred outside the application container, e.g., by copying it or sending it to an external application. A keyboard cache feature may operate to disable the autocorrect functionality for sensitive text fields. SSL certificate validation may be operable so the application specifically validates the server SSL certificate instead of it being stored in the keychain. An encryption key generation feature may be used such that the key used to encrypt data on the device is generated using a passphrase or biometric data supplied by the user (if offline access is required). It may be XORed with another key randomly generated and stored on the server side if offline access is not required. Key Derivation functions may operate such that keys generated from the user password use KDFs (key derivation functions, notably Password-Based Key Derivation Function 2 (PBKDF2)) rather than creating a cryptographic hash of it. The latter makes a key susceptible to brute force or dictionary attacks.

Further, one or more initialization vectors may be used in encryption methods. An initialization vector might cause multiple copies of the same encrypted data to yield different cipher text output, preventing both replay and cryptanalytic attacks. This may also prevent an attacker from decrypting any data even with a stolen encryption key. Further, authentication then decryption may be used, wherein application data is decrypted only after the user has authenticated within the application. Another feature may relate to sensitive data in memory, which may be kept in memory (and not in disk) only when it's needed. For example, login credentials may be wiped from memory after login, and encryption keys and other data inside objective-C instance variables are not stored, as they may be easily referenced. Instead, memory may be manually allocated for these.

An inactivity timeout may be implemented, wherein after a policy-defined period of inactivity, a user session is terminated.

Data leakage from the application management framework 614 may be prevented in other ways. For example, when an application 610 is put in the background, the memory may be cleared after a predetermined (configurable) time period. When backgrounded, a snapshot may be taken of the last displayed screen of the application to fasten the foregrounding process. The screenshot may contain confidential data and hence should be cleared.

Another security feature relates to the use of an OTP (one time password) 620 without the use of an AD (active directory) 622 password for access to one or more applications. In some cases, some users do not know (or are not permitted to know) their AD password, so these users may authenticate using an OTP 620 such as by using a hardware OTP system like SecurID (OTPs may be provided by different vendors also, such as Entrust or Gemalto). In some cases, after a user authenticates with a user ID, a text is sent to the user with an OTP 620. In some cases, this may be implemented only for online use, with a prompt being a single field.

An offline password may be implemented for offline authentication for those applications 610 for which offline use is permitted via enterprise policy. For example, an enterprise may want StoreFront to be accessed in this manner. In this case, the client agent 604 may require the user to set a custom offline password and the AD password is not used. Gateway server 606 may provide policies to control and enforce password standards with respect to the minimum length, character class composition, and age of passwords, such as described by the standard Windows Server password complexity requirements, although these requirements may be modified.

Another feature relates to the enablement of a client side certificate for certain applications 610 as secondary credentials (for the purpose of accessing PKI protected web resources via the application management framework micro VPN feature). For example, an application may utilize such a certificate. In this case, certificate-based authentication using ActiveSync protocol may be supported, wherein a certificate from the client agent 604 may be retrieved by gateway server 606 and used in a keychain. Each managed application may have one associated client certificate, identified by a label that is defined in gateway server 606.

Gateway server 606 may interact with an Enterprise special purpose web service to support the issuance of client certificates to allow relevant managed applications to authenticate to internal PKI protected resources.

The client agent 604 and the application management framework 614 may be enhanced to support obtaining and using client certificates for authentication to internal PKI protected network resources. More than one certificate may be supported, such as to match various levels of security and/or separation requirements. The certificates may be used by the Mail and Browser managed applications, and ultimately by arbitrary wrapped applications (provided those applications use web service style communication patterns where it is reasonable for the application management framework to mediate https requests).

Application management client certificate support on iOS may rely on importing a public-key cryptography standards (PKCS) 12 BLOB (Binary Large Object) into the iOS keychain in each managed application for each period of use. Application management framework client certificate support may use a HTTPS implementation with private in-memory key storage. The client certificate might never be present in the iOS keychain and might not be persisted except potentially in “online-only” data value that is strongly protected.

Mutual SSL or TLS may also be implemented to provide additional security by requiring that a mobile device 602 is authenticated to the enterprise, and vice versa. Virtual smart cards for authentication to gateway server 606 may also be implemented.

Both limited and full Kerberos support may be additional features. The full support feature relates to an ability to do full Kerberos login to Active Directory (AD) 622, using an AD password or trusted client certificate, and obtain Kerberos service tickets to respond to HTTP Negotiate authentication challenges. The limited support feature relates to constrained delegation in Citrix Access Gateway Enterprise Edition (AGEE), where AGEE supports invoking Kerberos protocol transition so it can obtain and use Kerberos service tickets (subject to constrained delegation) in response to HTTP Negotiate authentication challenges. This mechanism works in reverse web proxy (aka corporate virtual private network (CVPN)) mode, and when http (but not https) connections are proxied in VPN and MicroVPN mode.

Another feature relates to application container locking and wiping, which may automatically occur upon jail-break or rooting detections, and occur as a pushed command from administration console, and may include a remote wipe functionality even when an application 610 is not running.

A multi-site architecture or configuration of enterprise application store and an application controller may be supported that allows users to be service from one of several different locations in case of failure.

In some cases, managed applications 610 may be allowed to access a certificate and private key via an API (example OpenSSL). Trusted managed applications 610 of an enterprise may be allowed to perform specific Public Key operations with an application's client certificate and private key. Various use cases may be identified and treated accordingly, such as when an application behaves like a browser and no certificate access is used, when an application reads a certificate for “who am I,” when an application uses the certificate to build a secure session token, and when an application uses private keys for digital signing of important data (e.g. transaction log) or for temporary data encryption.

Illustrative Examples of Secure Authentication of a Device Through Attestation by Another Device

Methods and systems for secure authentication of a device through attestation by one or more trusted devices are described herein. In some examples, the device and trusted device(s) may comprise mobile devices. The authentication method may leverage users' natural ability to recognize each other and the natural network of trust in an organization. For example, a user (e.g., user A) may identify him or herself or authenticate weakly to a server, such as by sending a username and password or other credentials. The server may generate a human-readable description of the user's identity claims (e.g., full name, device type, etc.). Another user (e.g., user B), who may both know user A and may be able to strongly authenticate to the server, may verify those claims. User B may send, via his or her device, an attestation back to the server stating that the claims are correct. In some aspects, the server may be able to strongly authenticate user B and have greater confidence that the user A's authentication is legitimate and that user A's device can be trusted. For example, user B's device may already be registered and trusted by the server. In some aspects, user B may be specially privileged, such as a system administrator. In other aspects, user B might not be specially privileged. Methods and systems described herein may be used for, for example, self-service password reset or registering an untrusted device with the server.

FIG. 7 depicts an illustrative system 700 and method for secure authentication of a device through attestation by another device in accordance with one or more illustrative aspects described herein. The system 700 may comprise one or more servers, such as server 730. The server 730 may be used to authenticate and/or register client devices. The system 700 may comprise one or more additional servers (not illustrated), which may be used to authenticate and/or register client devices. The system 700 may comprise a plurality of client devices, such as device A 720 and device B 740. The system 700 may comprise one or more other client devices (not illustrated). Each device may be, for example, client device 107 or 109 illustrated in FIG. 1, client device 240 illustrated in FIG. 2, mobile device 502 illustrated in FIG. 5, mobile device 602 illustrated in FIG. 6, or any other client device. Each client device may run an application, and the application may be used by the client device to communicate with other client devices and/or to communicate with one or more servers (e.g., server 730). The application may also provide (e.g., display) an interface for authentication and/or attestation, as will be described in further detail below.

In step 701, user A may begin using an application on device A 720 associated with user A. In some aspects, device A 720 may be a new device that is attempting to authenticate with the server 730 and/or to enroll with one or more services (e.g., resources) provided by the server 730. In some aspects, one or more other devices, such as device B 740, may already be authenticated and/or enrolled with the server 730. As will be described in further detail below, device B 740 may be used to attest to or verify the identity of user A and/or device A 720.

In step 702, user A may input credentials via the application on device A 720. For example, user A may submit a username and password, biometrics (e.g., a fingerprint, voiceprint, face scan, etc.), a token or certificate, or any other type of credential. Device A 720 may receive the credentials from user A via the application and may transmit the credentials to the server 730. The server 730 may authenticate user A based on the received credentials. After authenticating user A based on the credentials, the server 730 may determine to request attestation of user A's identity. Accordingly, device A 720 may be authenticated via multi-factor authentication.

In step 703, the server 730 may generate a challenge code, such as a one-time challenge code. The challenge code may identify and/or be unique to user A's authentication attempt. The challenge code may be used by the server 730 to associate user A's authentication attempt with user B's attestation, as will be described in further detail below. For example, a one-time challenge code may comprise a random number generated by a random number generator of the server 730. As another example, the challenge code may comprise a number generated by a sequential ID counter. The server 730 may increment the number (e.g., by 1, by 10, etc.) each time the server 730 requests attestation of an authentication attempt by a device. The server 730 may generate a request to device A 720 for an authentication attestation. Data included in the attestation request may comprise, for example, the challenge code, an identifier for the server 730 (e.g., a uniform resource identifier (URI), such as a uniform resource locator (URL)), and/or a set of human-understandable information that identifies user A and/or device A 720 (e.g., user A's name, user A's email address, user A's office location, the type of device of device A 720, etc.).

In some aspects, the request may include data indicating which users, group(s) of users, and/or device(s) are authorized to attest to user A's identity. Alternatively, the server 730 may transmit, separately from the attestation request, the data indicating which users, group(s) of users, and/or device(s) are authorized to attest to user A's identity. The data may indicate a list of users, a list of devices, or group information, such as users in the same security group as user A, one or more managers of user A, one or more members on user A's team, and the like. Group information may be stored at (or otherwise accessible to) server 730. The server 730 may transmit, to device A 720, the request with the challenge code, server identifier, information identifying user A and/or device A 720, and/or a list of authorized users, devices, and/or groups.

In step 704, the client device A 720 may encode, via the application, one or more of the pieces of data included in the attestation request received from the server 730. The client device A 720 may encode the challenge code, the server identifier, and/or the information identifying user A and/or device A 720. For example, the client device A 720 may encode the data from the server 730 as a code, such as a one-dimensional code, a two-dimensional code (e.g., a Quick Response (QR) code), or an n-dimensional code. As will be described in further detail below, the code may be displayed on a display of device A 720 and scanned by another device, such as device B 740. Device B 740 may be associated (e.g., owned, operated, managed, etc.) with a different user (e.g., user B). Additionally or alternatively, device B 740 may be associated with the user attempting authentication (e.g., user A), such as if user A has two (or more) different devices and one of those devices (e.g., device B 740) is already trusted by server 730. In some aspects, the information to send to device B 740 may be stored at the server 730 or another location accessible to device B 740 (or other devices used to attest to user A's identity). In these examples, device A 720 may encode a URL to the location of the information stored at server 730. The device A 720 may display, via the application and on a display of the client device A 720, the QR code (or other code), along with instructions to user A to find a third party, such as user B, and/or another device, such as device B 740, to attest to user A's identity. The device A 720 may also display, to user A, a list of users, groups of users, and/or device(s) that are authorized to attest to user A's identity. As will be described in further detail below, user B (or user A) of device B 740 may capture an image of the QR code displayed on device A and use the information encoded in the QR code to attest to user A's identity.

Data may be shared between devices via other channels. For example, user A may be instructed to move the device A 720 within range of device B 740 to transmit the challenge code, server identifier, and/or information identifying user A and/or device A 720 to device B 740 via, for example, near-field communication (NFC). In some aspects, device A 720 may display the challenge code, server identifier, and/or information identifying user A and/or device A 720 in plaintext, and user B may view the information on device A 720 and manually input the information into device B 740.

In step 705, user B (or user A) may open an application on device B 740 and use device B's camera to scan the code (e.g., QR code) displayed on device A 720. Device B 740 may decode the data encoded in the code. By scanning and decoding the code, device B 740 may access the challenge code from the server 730, server identifier, and/or information identifying user A and/or device A 720. As previously explained, the data may be directly encoded on the code. Alternatively, the data may be stored at the server 730 (or another storage location), and device B 740 may use a URL encoded in the code to access the data. In some aspects, user A and user B may be at different locations (e.g., different buildings, cities, countries, etc.). User A may use a webcam to capture an image of display device A 720 displaying the QR code, and user B may scan the QR code captured by the webcam.

In step 706, the application on device B 740 may display one or more pieces of the data from server 730 (e.g., the challenge code, server identifier, and/or information identifying user A and/or device A 720). User B may review the displayed information and confirm that the information is accurate. For example, user B may confirm user A's location, email address, username, photograph, device information, etc.

In step 707, user B (or user A) may authenticate with server 730 using device B 740 via, for example, strong authentication. Device B 740 may identify server 730 using the server identifier received from device A 720. In some aspects, device B 740 may be registered with the server 730. The server 730 may have previously sent a security certificate (e.g., x509 certificate) to device B 740, and device B 740 may have stored the security certificate for future use (e.g., for future authentication with server 730). User B (or user A) may authenticate with server 730 using the stored certificate, such as by transmitting the certificate to the server 730 via device B 740. User B (or user A) may additionally or alternatively provide other credentials to server 730, such as username and password. Server 730 may authenticate device B 740 based on the security certificate or other credentials.

In step 708, device B 740 may transmit, to server 730, one or more pieces of the data from server 730 (e.g., the challenge code and/or information identifying user A and/or device A 720). Device B 740 may also transmit a confirmation that the information from device A 720 is true and that user A's authentication attempt is legitimate. Server 730 may receive, from device B 740, the challenge code, the information identifying user A and/or device A 720, and/or the confirmation. In some aspects, device B 740 may act as a second (or n-th) authentication factor for user A of device A 720.

In step 709, the server 730 may verify that the data received from device B 740 corresponds to the data sent to device A 720 (e.g., in step 703). For example, the server 730 may compare the received challenge code to the challenge code the server 730 previously generated. The server 730 may also verify the information identifying user A and/or device A 720. The server 730 may also verify that user B is part of the group of users that can attest to user A's identity. If the information is verified, server 730 may accept the attestation of user A by device B 740.

In step 710, the server 730 may transmit, to the device 720 A, an indication that user A has been granted access to one or more resources provided by server 730 and/or may register device A 720 to be used for strong authentication in future. The device 720 A may receive the indication from the server 730. In some aspects, device A 720 may now be used to attest to the identity of other users.

In some aspects, the server 730 may request attestation from a plurality of users or devices (e.g., two devices, three devices, and the like) before granting user A access to resources and/or registering device A 720. For example, after user B attests to user A's identity, user A may find another user, such as user C, to also attest to user A's identity. The method may repeat steps 705, 706, 707, 708, and/or 709 described above for another client device. The server 730 may track the number of times user A has been verified by other authorized users. The server 730 may also transmit, to device A 720, an indication of the number, and device A 720 may display the number to user A so that user A knows how many more attestations are needed. Once user A has been verified by a threshold number of other users, server 730 may grant user A access to one or more resources provided by server 730 and/or may register device A 720, as previously described with reference to step 710.

In some aspects, the level of access device A 720 has to resources may be based on the number of attestations of user A. For example, server 730 may grant device A 720 read access to one or more files if one device (e.g., device B 740) attests to user A's identity. Server 730 may grant device A 720 write access to the one or more files if two devices (e.g., device B 740 and another device) attest to user A's identity. Device A 720 may be granted greater access privileges the more devices attest to user A's identity. In some aspects, the level of access device A 720 has to resources may be based on the level of access of other devices used to attest to user A's identity. For example, device A 720 may access resources that device B 740 can access if device B 740 attests to user A's identity. If another device with higher (or lower) access privileges attests to user A's identity, server 730 may grant device A 720 access to resources that that other device can access.

FIG. 8 depicts another illustrative system and method for secure authentication of a device through attestation by another device in accordance with one or more illustrative aspects described herein. The system 700 may comprise a plurality of servers, such as server 730 and server 850. The servers may be used together to authenticate and/or register client devices. For example, user A and user B may authenticate to different servers (e.g., server A 730 and server B 850, respectively). In larger deployments, user A and user B may connect to different server instances, such that the user A's server 730 does not directly trust user B.

In step 801, user A may begin using an application on device A 720 associated with user A. In some aspects, device A 720 may be a new device that is attempting to authenticate with the server 730 and/or to enroll with one or more services (e.g., resources) provided by the server 730. In some aspects, one or more other devices, such as device B 740, may already be authenticated and/or enrolled with the server 730 or server 850. As will be described in further detail below, device B 740 may be used to attest to or verify the identity of user A and/or device A 720.

In step 802, user A may input credentials via the application on device A 720. For example, user A may submit a username and password, biometrics (e.g., a fingerprint, voiceprint, face scan, etc.), a token or certificate, or any other type of credential. Device A 720 may receive the credentials from user A via the application and may transmit the credentials to the server 730. The server 730 may authenticate user A based on the received credentials. After authenticating user A based on the credentials, the server 730 may determine to request attestation of user A's identity. Accordingly, device A 720 may be authenticated via multi-factor authentication.

In step 803, the server 730 may generate a challenge code, such as a one-time challenge code. The one-time challenge code may be unique to user A's authentication attempt. For example, the one-time challenge code may comprise a random number generated by a random number generator of the server 730. The server 730 may generate a request to device A 720 for an authentication attestation. Data included in the attestation request may comprise, for example, the challenge code, an identifier for the server 730 (e.g., a uniform resource identifier (URI), such as a uniform resource locator (URL)), an identifier for the server 850, and/or a set of human-understandable information that identifies user A and/or device A 720 (e.g., user A's name, user A's email address, user A's office location, the type of device of device A 720, etc.).

In some aspects, the request may include data indicating which users and/or group(s) of users are authorized to attest to user A's identity. For example, the data may indicate a list of users or group information, such as users in the same security group as user A, one or more managers of user A, one or more members on user A's team, and the like. Group information may be stored at (or otherwise accessible to) server 730. The server 730 may transmit, to device A 720, the request with the challenge code, server identifier, information identifying user A and/or device A 720, and/or a list of authorized users and/or groups.

In step 804, the client device A 720 may encode, via the application, one or more of the pieces of data included in the attestation request received from the server 730. The client device A 720 may encode the challenge code, the server identifier, and/or the information identifying user A and/or device A 720. For example, the client device A 720 may encode the data from the server 730 as a two-dimensional code, such as a Quick Response (QR) code. In some aspects, the information to send to device B 740 may be stored at the server 730 or another location accessible to device B 740, such as server 850. Device A 720 may encode a URL to the location of the information stored at server 730 or server 850. The device A 720 may display, via the application and on a display of the client device A 720, the QR code (or other code), along with instructions to user A to find a third party, such as user B, to attest to user A's identity. The device A 720 may also display, to user A, a list of users and/or groups of users that are authorized to attest to user A's identity.

Data may be shared between devices via other channels. For example, user A may be instructed to move the device A 720 within range of device B 740 to transmit the challenge code, server identifier, and/or information identifying user A and/or device A 720 to device B 740 via, for example, near-field communication (NFC). In some aspects, device A 720 may display the challenge code, server identifier(s), and/or information identifying user A and/or device A 720 in plaintext, and user B may view the information on device A 720 and manually input the information into device B 740.

In step 805, user B may open an application on device B 740 and use device B's camera to scan the code (e.g., QR code) displayed on device A 720. Device B 740 may decode the data encoded in the code. By scanning and decoding the code, device B 740 may access the challenge code from the server 730, server identifier(s), and/or information identifying user A and/or device A 720. As previously explained, the data may be directly encoded on the code. Alternatively, the data may be stored at the server 730, the server 850, or another storage location, and device B 740 may use a URL encoded in the code to access the data. For example, in step 805 b, device B 740 may use the URL to access the data from server 730. In some aspects, user A and user B may be at different locations (e.g., different buildings, cities, countries, etc.). User A may use a webcam to capture an image of display device A 720 displaying the QR code, and user B may scan the QR code captured by the webcam.

In step 806, the application on device B 740 may display one or more pieces of the data from server 730 (e.g., the challenge code, server identifier(s), and/or information identifying user A and/or device A 720). User B may review the displayed information and confirm that the information is accurate. For example, user B may confirm user A's location, email address, username, photograph, device information, etc.

In step 807, user B may authenticate with server 850 via, for example, strong authentication. Device B 740 may identify server 850 using the server identifier(s) received from device A 720. In some aspects, the server 850 may have previously sent a security certificate to device B 740, and device B 740 may have stored the security certificate for future use (e.g., for future authentication with server 850). User B may authenticate with server 850 using the stored certificate, such as by transmitting the certificate to the server 850 via device B 740. User B may additionally or alternatively provide other credentials to server 850, such as username and password. Server 850 may authenticate device B 740 based on the security certificate or other credentials.

Device B 740 may transmit, to server 850, one or more pieces of the data from server 730 (e.g., the challenge code and/or information identifying user A and/or device A 720). Device B 740 may also transmit a confirmation that the information from device A 720 is true and that user A's authentication attempt is legitimate. Server 850 may receive, from device B 740, the challenge code, the information identifying user A and/or device A 720, and/or the confirmation.

In step 808, the server 850 may forward the attestation confirmation to server 730. The server 850 may also transmit its own claims about the identity and trustworthiness of User B. Servers 730 and 850 may have previously established a trust relationship. For example, server 850 may provide an identity certificate to server 730, and server 730 may trust server 850 based on the identity certificate. Server 730 and 850 may establish a trust relationship by a common firewall.

In step 809, the server 730 may verify that the data received from server B 850 corresponds to the data sent to device A 720 (e.g., in step 803). For example, the server 730 may compare the received challenge code to the challenge code the server 730 previously generated. The server 730 may also verify the information identifying user A and/or device A 720. The server 730 may also verify that user B is part of the group of users that can attest to user A's identity. If the information is verified, server 730 may accept the attestation of user A by device B 740.

In step 810, the server 730 may grant user A access to one or more resources provided by server 730 and/or may register device A 720 to be used for strong authentication in future. In some aspects, device A 720 may now be used to attest to the identity of other users. As previously explained, a plurality of devices may attest to user A's identity, and device A's access level may be based on the number of devices that attest to user A's identity.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are described as example implementations of the following claims. 

What is claimed is:
 1. A method comprising: receiving, by a server from an untrusted client device, a request for access to one or more services associated with the server; generating, by the server, a challenge code; sending, by the server to the untrusted client device, a request for attestation of the untrusted client device, wherein the request for attestation comprises the challenge code; receiving, by the server from a trusted client device, an indication that the trusted client device attests to an identity of the untrusted client device, wherein the indication comprises the challenge code; and based on the indication that the trusted client device attests to the identity of the untrusted client device, granting, by the server and to the untrusted client device, access to the one or more services associated with the server.
 2. The method of claim 1, wherein the challenge code comprises a one-time challenge code, and wherein the generating the challenge code comprises generating the challenge code using a random number generator associated with the server.
 3. The method of claim 1, wherein the request for attestation further comprises an identifier for the server.
 4. The method of claim 1, further comprising: determining a plurality of users authorized for attestation of the untrusted client device; and sending, by the server and to the untrusted client device, data indicating the plurality of users authorized for attestation of the untrusted client device.
 5. The method of claim 1, wherein the receiving the indication that the trusted client device attests to the identity of the untrusted client device is performed after an authentication of the trusted client device by a second server.
 6. The method of claim 1, wherein the granting access to the one or more services is further based on a determination that the challenge code received from the trusted client device matches the challenge code sent to the untrusted client device.
 7. The method of claim 1, further comprising: based on a quantity of one or more trusted client devices attesting to the identity of the untrusted client device, determining, by the server, a level of access of the untrusted client device to the one or more services associated with the server.
 8. The method of claim 1, further comprising: based on a level of access of the trusted client device to the one or more services associated with the server, determining, by the server, a level of access of the untrusted client device to the one or more services associated with the server.
 9. A system comprising: a server; an untrusted client device; and a trusted client device, wherein the server is configured to: receive, from the untrusted client, a request for access to one or more services associated with the server; generate a challenge code; and send, to the untrusted client device, a request for attestation of the untrusted client device, wherein the request for attestation comprises the challenge code, wherein the untrusted client device is configured to: encode the challenge code, wherein the trusted client device is configured to: receive, from the untrusted client device, the encoded challenge code; and send, to the server, an indication that the trusted client device attests to an identity of the untrusted client device, wherein the indication comprises the challenge code, and wherein the server is further configured to: based on the indication that the trusted client device attests to the identity of the untrusted client device, grant, to the untrusted client device, access to the one or more services associated with the server.
 10. The system of claim 9, wherein the untrusted client device is further configured to display the encoded challenge code, and wherein the trusted client device is configured to receive the encoded challenge code by scanning the encoded challenge code displayed by the untrusted client device.
 11. The system of claim 10, wherein the encoded challenge code comprises a quick response (QR) code.
 12. The system of claim 9, wherein the challenge code comprises a one-time challenge code, and wherein the generating the challenge code comprises generating the challenge code using a random number generator associated with the server.
 13. The system of claim 10, wherein the trusted client device is further configured to send, to the server, information identifying a user of the untrusted client device, and the server is configured to grant access to the one or more services associated with the server further based on the information identifying the user of the untrusted client device.
 14. The system of claim 10, wherein the trusted client device is further configured to: receive, from the untrusted client device, an identifier for the server; and authenticating with the server based on the identifier for the server.
 15. The system of claim 9, wherein the server is further configured to: based on a quantity of one or more trusted client devices attesting to the identity of the untrusted client device, determining a level of access of the untrusted client device to the one or more services associated with the server.
 16. A system comprising: a first server; a second server; an untrusted client device; and a trusted client device, wherein the first server is configured to: receive, from the untrusted client, a request for access to one or more services associated with the first server; and send, to the untrusted client device, a request for attestation of the untrusted client device, wherein the request for attestation comprises an identifier for the server, wherein the untrusted client device is configured to: encode the identifier for the server, wherein the trusted client device is configured to: receive, from the untrusted client device, the encoded identifier for the server; and receive, based on the encoded identifier for the server, authentication data; and send, to the second server and based on the authentication data, an indication that the trusted client device attests to an identity of the untrusted client device, wherein the second server is configured to: send, to the first server, the indication that the trusted client device attests to an identity of the untrusted client device, and wherein the first server is further configured to: based on the indication that the trusted client device attests to an identity of the untrusted client device, grant, to the untrusted client device, access to the one or more services associated with the first server.
 17. The system of claim 16, wherein the authentication data comprises at least one of: a challenge code, an identifier for the second server, an identifier for the untrusted client device, an identifier for a user of the untrusted client device, and an indication of one of more users who are authorized to attest to the identity of the untrusted client device.
 18. The system of claim 16, wherein the untrusted client device is further configured to display the encoded identifier for the server, and wherein the trusted client device is configured to receive the encoded identifier for the server by scanning the encoded identifier for the server displayed by the untrusted client device.
 19. The system of claim 16, wherein the second server is further configured to send, to the first server, an indication that the second server attests to the identity of the untrusted client device.
 20. The system of claim 16, wherein the second server is further configured to send a security certificate to the trusted client device, and wherein the trusted client device is further configured to: store the security certificate; and prior to sending the indication that the trusted client device attests to the identity of the untrusted client device, authenticate with the second server using the stored security certificate. 